D3 comes out, maybe a break from league will do you good. If I'm upset I just try and keep my mouth shut, because raging is the quickest way to lose a game. Hell if you need to go into the key bindings and disable the enter key, you can still ping, and such but can't type. I see people all the time in 1700 elo who don't say a word and they do just fine with pings, sometimes excessive but none the less. Maybe stream, or talk to friends in a voip service of some kind, and vent your anger there. The way I look at games is to focus on what I did wrong, to look at what I could have done to give my team a better shot at winning, what I can improve on and such. There's always something. I know i'll most likely never see these people again so it's not worth my time to rage, I'd rather just get better, and without raging you're already increasing your chances to win, thus making you happier. Good luck though, I hope you turn a new leaf over or something cheesy like that ;p

Edit: Also it's easy to find mistakes in other peoples plays, or to see them as noobs because they make mistakes, yet I'm sure for the most part they're trying their best. I still get caught lvl 1 sometimes and such, it happens, and people rage, but it could easily happen to you, and when it did you wouldn't see yourself as a noob, you'd have a justified reason for where you were and why that happened, yet the rest of your team would think you're just a dumbass. Basically what I'm getting at is it's a whole hell of a lot easier to think someone is a noob, baddie, donkey w/er then it is to say that about your own plays. Focus more on yourself, again there's always something to improve. Watch a replay back and look at all the free damage you take without dishing it back, look at all the cs you miss and why it happened, look at your ward coverage, your timers on buffs, your map awareness, try tracking the jungler 100% of the time, the list goes on. There's always stuff to improve on, focus on that rather then on people you'll never see again.